Platelet glycoprotein Illa polymorphisms and risk of coronary stent thrombosis

Background Coronary stents are an effective treatment for selected coronary stenoses. However, thrombosis of the stented segment is a major adverse complication. Platelet aggregation has a key role in stent thrombosis. We investigated whether a polymorphism of platelet glycoprotein Illa gene (PlA2) is associated with an increased risk of coronary stent thrombosis. Methods 318 consecutive patients were followed up for 30 days after coronary stent insertion. The primary endpoints were death, myocardial infarction, stent-vessel occlusion, and coronary artery bypass surgery. Gel electrophoresis of PCR products was used to identify the PlA1 and PlA2 alleles. The relative risk of stent occlusion was calculated from the odds ratio on logistic regression analysis. Findings 63 (19·8%) of patients had the PlA2 allele and 255 (80·2%) were homozygous for PlA1. Baseline clinical, angiographic, and procedural features did not differ between the groups with and without the PlA2 allele. Occlusion of the stent vessel occurred in five (1·9%) patients homozygous for PlA1 and six (9·5%) patients with PlA2 allele (odds ratio 5·26 [95% Cl 1·55–17·85]). On multivariate regression analysis PlA1/A2 genotype was the only significant independent predictor of stent thrombosis. Interpretation Patients with the PlA2 allele have an increased risk of coronary stent thrombosis, which may warrant antiplatelet therapy with glycoprotein-llb/Illa inhibitors, although bleeding complications may also increase.